I have a 91 civic and the idle seems to be hunting, there is no check engine light and I was wondering if anyone else has had a similar problem, I tuned the car up about 5000 miles ago.

 

does it only do it when the engine is cold or when it is warmed up?

 

It does it all the time, while the car is idling, it will slowly increase and decrease the idle speed. It is not a major jump in idle speed just a slight increase.

 

You may have a vacuum leak of the intake manifold some where (hoses get old and crack).

Try resetting the idle to see if that fixes it...If you have a DX or STD it's to the passenger side left of the tb (tb sits like a carbuerator), Si or it's on the front or back